1. Technical Field
The present disclosure relates to an antenna device for carrying out wireless communications, and a wireless communication apparatus including the same.
2. Background Art
FIG. 8 is an external view showing an example of a cellular phone as a wireless communication apparatus (refer to Patent Document 1) as viewed from a back side. FIG. 8 is a perspective view showing a case where an LCD (liquid crystal display) and a key unit are provided on the opposite side to that shown in the figure. A cellular phone 40 shown in FIG. 8 includes an antenna element 42 and a non-feeding element 43 contained within a case 41. The antenna element 42 is configured so as to receive RF power from a feeding section 44 at a middle portion of the antenna.
The non-feeding element 43 and the antenna element 42 are provided on the same plane with a mutual gap therebetween, and, for example, attached to an internal wall of the case 41. The non-feeding element 43 is provided near a top end of the interior of the case 41. The antenna element 42 is provided below the non-feeding element 43. The antenna element 42 and the non-feeding element 43 are electromagnetically coupled to each other.
Patent Document 1: Japanese Patent No. 3608735
Cellular phones that are available have various shapes, and the variety is expected to increase. Thus, there is a demand for reduction of an antenna providing space in a cellular phone compared with currently available sizes. However, in the cellular phone 40, the antenna element 42 and the non-feeding element 43 are provided on the same plane with a mutual gap, with the antenna element 42 formed below the non-feeding element 43 (toward the bottom of the phone). Therefore, design flexibility of these elements 42 and 43 is low. Furthermore, antenna characteristics improve as the amount of separation from a ground terminal increases. Thus, it is disadvantageous from the perspective of antenna characteristics to locate the antenna element 42 and the non-feeding element 43 such that the amount of separation of the antenna element 42 is less than the amount of separation of the non-feeding element 43.
That is, in a configuration where a feeding element such as an antenna element and a non-feeding element are provided on the same plane, a design attempt to provide a needed amount of separation from a ground terminal could increase the size of an antenna device. Therefore, it has been difficult to reduce the size of an antenna device or a wireless communication apparatus including an antenna device.